Telecommunication carriers are required by government regulations to provide emergency calling services to their customers. In the United States and Canada, 911 is the official emergency phone number that callers can dial in order to reach dispatch personnel at a public safety answering points (PSAP). When a caller dials 911 from a telephone, the call is routed by a carrier to receiving equipment at a PSAP facility. A dispatcher at the facility answers the call and assists the caller with their emergency.
Often times, dispatchers must dispatch first responder personnel to the scene of an emergency to render assistance to callers. In the past, dispatchers had to ask a caller for his location. Over time, most telecommunication carriers developed the capability to automatically determine the location of caller who dialed 911 via a landline. For instance, 911 callers on a landline can be located based on their phone number. In the case of broadband 911 voice calls, callers can be located based on the identity of their broadband equipment.
During the course of a 911 call made from a mobile phone, a PSAP or other emergency services provider may request the carrier determine the approximate location of a mobile 911 caller. Once the carrier determines an approximate location of a mobile caller, this information may be relayed to the PSAP. One method of providing this approximate location is to give the requestor the location of the radio tower servicing the 911 call. This approximate location may also be used to determine which PSAP should receive the 911 call.
Government regulations, however, do not allow a carrier to make certain changes to its location determinations without following certain procedures or meeting certain standards. For example, consider the case where a carrier moves a cell tower from inside city limits to outside city limits and this new location would result in new location information being provided by the carrier to a PSAP. For example, this new location may change the PSAP that services the mobile 911 calls routed through that tower from the municipal PSAP to the county PSAP. To make this change, one or both of the county and municipal PSAP's may need to consent.
To obtain this consent, or otherwise satisfy the requirements of a regulatory scheme, time consuming or expensive procedures or tests may need to be conducted such as a drive test. A drive test may involve sending personnel out to various locations in a PSAP's service area to determine if the routing of mobile 911 calls is to the proper PSAP. Or a drive test may check that the location being provided by the carrier meets certain accuracy criteria. Accordingly, because changing the information used to make mobile 911 location determinations might effect the location determinations provided by the carriers location determination equipment, there is a problem modifying the information used to make mobile 911 call location determinations without incurring possibly unnecessary expense and time consuming procedures.